1. Field of the Invention
The invention generally relates to an optical device, and more particularly, to a light guide plate and a backlight module.
2. Description of Related Art
A backlight module usually includes a light guide plate, and the light guide plate guides the scatter direction of a light beam emitted by a light source to improve the brilliance of a panel and to insure the brightness uniformity of the panel, so as to convert a point light source or a line light source of the backlight module into a surface light source for a liquid crystal display panel. Therefore, the material properties of the light guide plate, the design and manufacture of the surface scatter pattern all relate to the entire optical design of the backlight module and the control of the brilliance and uniformity. Generally, the light guide plate includes a plurality of dots to destroy the total reflection for the light beam transmitting outside the backlight module. With the design of the dots, the light guide plate may emit the light beam uniformly.
Screen printing is a conventional process to make dots, and the disadvantage of the conventional process is that the diameters of the dots are limited by process technology so that it is hard to form small dots (e.g. the diameter of dots is hard to be less than 100 microns). Thus the thickness of the light guide plate may be limited, and if the light guide plate is too thin, the light guide plate may not be used because the user is easy aware of the flaw and the shape of dots. With the tendency towards the thin light guide plate, the inkjet technology used in making dots is disclosed. For example, Taiwan patent publication No. 1287135 discloses a display device, the display device includes a light guide plate having a plurality of microstructures and a reflector, wherein the microstructures are made on a side of the reflector adjacent to the light guide plate by using the inkjet technology.
In other hand, Taiwan patent application No. 200732785. discloses a method of making microstructures in the light guide plate by inkjet, wherein a number density of the microstructures adjacent to a light emitting surface of the light plate is smaller than a number density of the microstructures away from the light emitting surface of the light guide plate. Additionally, Taiwan patent application No. 200804924 discloses a direct type backlight module. The backlight module includes a plurality of curved light-uniformed elements and a plurality of light sources, wherein the light-uniformed element is similar to a diffusion sheet, and the light-uniformed element is aligned with a light source. Besides, US patent application No. 20060291065 discloses a micro lens, and an array of lenses foamed on a base sheet for deflecting a light beam.